/* ==========================================================================
   The lesson engine, shared by every lesson page.

   A lesson is a workbook; a step is a sheet. One sheet shows at a time on a
   full-width stage, advanced by the tab strip, the Prev/Next buttons, or the
   arrow keys. style.css supplies the tokens (--accent, --ink, --panel, …) and
   the topbar chrome; this file is only the engine.
   ========================================================================== */

.lwrap { max-width: 900px; margin: 0 auto; padding: 0 24px; }

/* ---- lesson header: the workbook name + the progress rail ---- */
.lhead { padding: 28px 0 14px; }
.lhead .kicker { font: 600 11px var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--faint); }
.lhead .kicker b { color: var(--accent); font-weight: 600; }
.lhead h1 { font: 600 clamp(24px, 4vw, 34px)/1.1 var(--sans); letter-spacing: -0.02em; margin: 10px 0 0; color: var(--ink); }
.lhead .wbmeta { margin-top: 10px; display: flex; align-items: center; gap: 12px; flex-wrap: wrap; font: 500 12px var(--mono); color: var(--muted); }
.lprog { flex: 1; min-width: 160px; height: 5px; border-radius: 99px; background: var(--line); overflow: hidden; }
.lprog i { display: block; height: 100%; width: 0; background: var(--accent); border-radius: 99px; transition: width 0.35s ease; }

/* ---- the sheet stage ---- */
.stage { position: relative; margin-top: 8px; }
.sheet { display: none; animation: sheetin 0.34s ease; }
.sheet.on { display: block; }
@media (prefers-reduced-motion: reduce) { .sheet { animation: none; } }
@keyframes sheetin { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }

.sheet-card {
  background: var(--panel); border: 1px solid var(--line); border-radius: 8px;
  padding: 30px 32px 34px; min-height: 60vh;
}
@media (max-width: 560px) { .sheet-card { padding: 22px 20px 26px; } }
.sheet-n { font: 600 11px var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent); }
.sheet-card h2 { font: 600 clamp(21px, 3.2vw, 27px)/1.18 var(--sans); letter-spacing: -0.015em; margin: 8px 0 0; color: var(--ink); text-wrap: balance; }
.sheet-card p { font-size: 15.5px; line-height: 1.62; color: var(--muted); margin: 14px 0 0; max-width: 64ch; }
.sheet-card p b { color: var(--ink); font-weight: 600; }
.sheet-card ul, .sheet-card ol { margin: 12px 0 0 2px; padding-left: 20px; }
.sheet-card li { font-size: 15px; line-height: 1.6; color: var(--muted); margin: 6px 0; }
.sheet-card li b { color: var(--ink); }
.sheet-card .lede { font-size: 17px; color: var(--ink); }
.sheet-card code, .kbd {
  font: 500 13px var(--mono); background: var(--accent-dim); color: var(--ink);
  padding: 2px 6px; border-radius: 4px; border: 1px solid color-mix(in srgb, var(--accent) 20%, var(--line));
}

/* the live-embed frame (Sheet 1: "here is the thing you are about to own") */
.embed-wrap { margin-top: 18px; border: 1px solid var(--line); border-radius: 6px; overflow: hidden; background: #fff; }
.embed-wrap .cap { display: flex; align-items: center; gap: 8px; padding: 8px 13px; border-bottom: 1px solid var(--line); font: 500 11.5px var(--mono); color: var(--faint); }
.embed-wrap .cap .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); flex: none; }
.embed-wrap iframe { display: block; width: 100%; height: 300px; border: 0; background: #fff; }

/* ---- the Prompt Rail: copy-paste blocks the learner gives Claude ---- */
.rail { margin-top: 20px; border-radius: 8px; overflow: hidden; border: 1px solid var(--line); }
.rail + .rail { margin-top: 12px; }
.rail-head { display: flex; align-items: center; gap: 10px; padding: 9px 14px; font: 600 11px var(--mono); letter-spacing: 0.12em; text-transform: uppercase; }
.rail-head .what { color: var(--muted); font-weight: 500; letter-spacing: 0.02em; text-transform: none; font-size: 12px; }
.rail-copy {
  margin-left: auto; font: 600 10.5px var(--mono); letter-spacing: 0.08em; text-transform: uppercase;
  border: 1px solid currentColor; border-radius: 4px; padding: 4px 10px; background: transparent;
  cursor: pointer; opacity: 0.8; transition: opacity 0.12s;
}
.rail-copy:hover { opacity: 1; }
.rail-body { padding: 14px 16px; background: var(--panel); }
.rail-body pre { margin: 0; font: 500 13px/1.55 var(--mono); color: var(--ink); white-space: pre-wrap; word-break: break-word; }
/* the four rail colors */
.rail.build  { border-color: color-mix(in srgb, #1d5c8c 40%, var(--line)); }
.rail.build  .rail-head { background: #e8f0f8; color: #1d5c8c; }
.rail.test   { border-color: color-mix(in srgb, #5a6d1f 40%, var(--line)); }
.rail.test   .rail-head { background: #eef3e2; color: #5a6d1f; }
.rail.verify { border-color: color-mix(in srgb, #8b5a1f 40%, var(--line)); }
.rail.verify .rail-head { background: #f8efe2; color: #8b5a1f; }
.rail.fix    { border-color: color-mix(in srgb, #8b3a3a 40%, var(--line)); }
.rail.fix    .rail-head { background: #f8e6e6; color: #8b3a3a; }
@media (prefers-color-scheme: dark) {
  .rail.build  .rail-head { background: color-mix(in srgb, #1d5c8c 26%, var(--panel)); color: #7fb2d6; }
  .rail.test   .rail-head { background: color-mix(in srgb, #5a6d1f 26%, var(--panel)); color: #aec36e; }
  .rail.verify .rail-head { background: color-mix(in srgb, #8b5a1f 26%, var(--panel)); color: #d1a06a; }
  .rail.fix    .rail-head { background: color-mix(in srgb, #8b3a3a 26%, var(--panel)); color: #d68f8f; }
}

/* ---- retrieval chip: a recall question that reveals its answer ---- */
/* display/white-space/cursor/gap reset the pill `.chip` in style.css, which would
   otherwise lay the question, button and answer out as one nowrap flex row. */
.chip {
  display: block; white-space: normal; cursor: default; gap: 0;
  margin-top: 18px; border: 1px dashed color-mix(in srgb, var(--accent) 40%, var(--line));
  border-radius: 8px; padding: 14px 16px; background: var(--accent-dim); color: var(--ink);
}
.chip:hover { border-color: color-mix(in srgb, var(--accent) 40%, var(--line)); color: var(--ink); }
.chip .q { font: 600 13px var(--sans); color: var(--ink); }
.chip .q::before { content: 'Before you start  '; font: 600 10.5px var(--mono); letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); display: block; margin-bottom: 5px; }
.chip .reveal { margin-top: 10px; font: 600 11px var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--accent); background: transparent; border: 0; cursor: pointer; padding: 0; }
.chip .reveal:hover { text-decoration: underline; }
.chip .a { margin-top: 8px; font-size: 14px; color: var(--muted); display: none; }
.chip.open .a { display: block; animation: chip-drop 0.16s ease-out; }
@keyframes chip-drop { from { opacity: 0; transform: translateY(-4px); } }
.chip.open .reveal { display: none; }

/* ---- inline mechanism diagram (Lesson 1, Sheet 4: how the pointer connects) ---- */
/* Everything is drawn with class selectors, not presentation attributes, so the
   fills/strokes read the same --tokens as the rest of the page and flip in dark. */
.dgram { margin-top: 20px; border: 1px solid var(--line); border-radius: 8px; background: var(--panel); padding: 18px 18px 14px; overflow-x: auto; }
.dgram svg { display: block; width: 100%; min-width: 560px; height: auto; }
.dgram figcaption { margin-top: 12px; font: 500 12.5px/1.5 var(--mono); color: var(--faint); text-align: center; letter-spacing: 0.01em; }
.dgram figcaption b { color: var(--accent); font-weight: 600; }
.df-app     { fill: var(--panel); stroke: var(--line); }
.df-host    { fill: var(--bg); stroke: var(--line); }
.df-tile    { fill: var(--panel-2); }
.df-chip    { fill: var(--panel); stroke: var(--line); }
.df-bar     { fill: var(--faint); }
.df-dot     { fill: var(--faint); }
.df-sep     { stroke: var(--line); }
.df-zone    { fill: var(--accent-dim); stroke: var(--accent); }
.df-pill    { fill: none; stroke: var(--accent); }
.df-flow      { stroke: var(--accent); fill: none; }
.df-flow-dash { stroke: color-mix(in srgb, var(--accent) 55%, transparent); fill: none; }
.df-arrow   { fill: var(--accent); }
.df-t-ink    { fill: var(--ink);    font-family: var(--sans); }
.df-t-muted  { fill: var(--muted);  font-family: var(--sans); }
.df-t-mono   { fill: var(--muted);  font-family: var(--mono); }
.df-t-faint  { fill: var(--faint);  font-family: var(--mono); }
.df-t-accent { fill: var(--accent); font-family: var(--mono); }

/* ---- Try-it demo (Lesson 1, Sheet 5): load a .trex, edit it, watch it redraw ---- */
/* One blanket rule dodges the [hidden]-vs-display:flex specificity trap: any element
   the demo JS hides with the `hidden` property stays hidden no matter its display. */
.trydemo [hidden] { display: none !important; }
.trydemo { position: relative; margin-top: 20px; border: 1px solid var(--line); border-radius: 10px; background: var(--panel); overflow: hidden; }
.td-head { display: flex; align-items: baseline; gap: 10px; padding: 11px 15px; border-bottom: 1px solid var(--line); background: var(--accent-dim); }
.td-k { font: 600 11px var(--mono); letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); }
.td-sub { font: 500 11.5px var(--mono); color: var(--faint); }
.td-stage { display: grid; grid-template-columns: 188px 1fr; gap: 14px; padding: 15px; }
@media (max-width: 560px) { .td-stage { grid-template-columns: 1fr; } }

.td-files { display: flex; flex-direction: column; gap: 10px; align-items: flex-start; }
.td-files-h { font: 600 10px var(--mono); letter-spacing: 0.1em; text-transform: uppercase; color: var(--faint); }
.td-file { display: inline-flex; align-items: center; gap: 8px; padding: 10px 12px; border: 1px solid var(--line-bright); border-radius: 8px; background: var(--bg); cursor: grab; user-select: none; }
.td-file:active { cursor: grabbing; }
.td-file-ic { color: var(--accent); font-size: 14px; line-height: 1; }
.td-file-nm { font: 600 12.5px var(--mono); color: var(--ink); }
.td-note { font: 500 11px/1.5 var(--mono); color: var(--faint); }

.td-tab { border: 1px solid var(--line); border-radius: 9px; overflow: hidden; background: var(--bg); }
.td-bar { display: flex; align-items: center; gap: 7px; padding: 7px 11px; background: var(--panel-2); border-bottom: 1px solid var(--line); }
.td-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--faint); opacity: 0.5; }
.td-title { margin-left: 4px; font: 500 11px var(--mono); color: var(--muted); }
.td-body { position: relative; min-height: 178px; display: flex; }

.td-zone { flex: 1; margin: 14px; border: 2px dashed color-mix(in srgb, var(--accent) 45%, var(--line)); border-radius: 8px; display: flex; align-items: center; justify-content: center; text-align: center; padding: 12px; transition: background 0.12s, border-color 0.12s; }
.td-zone.over { border-color: var(--accent); background: var(--accent-dim); }
.td-zone-t { font-size: 14px; color: var(--ink); }
.td-zone-s { font: 500 11px var(--mono); color: var(--faint); margin: 8px 0; }

.td-canvas { flex: 1; position: relative; display: flex; align-items: center; justify-content: center; background: #eef1f6; padding: 16px; }
.td-badge { position: absolute; z-index: 2; top: 10px; left: 10px; font: 600 9.5px var(--mono); letter-spacing: 0.1em; color: var(--accent); border: 1px solid color-mix(in srgb, var(--accent) 45%, transparent); background: var(--accent-dim); border-radius: 4px; padding: 2px 7px; }

/* the real KPI card the demo renders (a faithful mock of kit/kpi-card): driven by
   --acc for the accent and [data-cardtheme] for light/dark, both set live by the
   style picker below. Serif number echoes the shipping card's Fraunces. */
.kpimock {
  --acc: #FE6A45;
  --card-bg: #ffffff; --card-ink: #131B33; --card-muted: #6A788F; --card-line: #E4E8F0;
  position: relative; width: 100%; max-width: 300px; overflow: hidden;
  background: var(--card-bg); color: var(--card-ink);
  border: 1px solid var(--card-line); border-radius: 12px; padding: 15px 18px 14px;
  box-shadow: 0 6px 20px rgba(16, 24, 45, 0.08);
  transition: background 0.25s, color 0.25s, border-color 0.25s;
}
.kpimock[data-cardtheme="dark"] {
  --card-bg: #0C1230; --card-ink: #F0F1F7; --card-muted: #8091B6; --card-line: #26305C;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
}
.kpimock-strip { position: absolute; top: 0; left: 0; right: 0; height: 3.5px;
  background: linear-gradient(90deg, var(--acc), color-mix(in srgb, var(--acc) 55%, #F3BE6A)); }
.kpimock-label { display: flex; align-items: center; gap: 0.55em; font: 600 11px var(--mono);
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--card-muted); }
.kpimock-tick { flex: none; width: 16px; height: 2px; border-radius: 2px; background: var(--acc); }
.kpimock-value { margin-top: 5px; font: 600 38px/1 Georgia, 'Times New Roman', serif; letter-spacing: -0.02em; color: var(--card-ink); }
.kpimock-unit { font: 600 0.42em var(--mono); color: var(--acc); margin-left: 0.1em; vertical-align: 0.5em; }
.kpimock-delta { display: flex; align-items: center; gap: 0.5em; margin-top: 8px; flex-wrap: wrap; }
.kpimock-chip { display: inline-flex; align-items: center; padding: 0.18em 0.55em; border-radius: 999px;
  font: 600 12px var(--mono); color: #0F9D6B; background: rgba(15, 157, 107, 0.12); border: 1px solid rgba(15, 157, 107, 0.28); }
.kpimock-vs { font: 500 11px var(--mono); color: var(--card-muted); }
.kpimock-spark { display: block; width: 100%; height: auto; margin-top: 10px; overflow: visible; }
.kpimock-area { fill: color-mix(in srgb, var(--acc) 16%, transparent); stroke: none; }
.kpimock-line { fill: none; stroke: var(--acc); stroke-width: 2.2; stroke-linecap: round; stroke-linejoin: round; }
.kpimock-dot { fill: var(--acc); stroke: var(--card-bg); stroke-width: 1.5; }
.kpimock-brace { position: absolute; right: 0.02em; bottom: -0.16em; font: 600 96px/1 Georgia, 'Times New Roman', serif;
  color: var(--acc); opacity: 0.09; pointer-events: none; user-select: none; }

.td-btn { font: 600 11.5px var(--mono); letter-spacing: 0.02em; border: 1px solid var(--accent); color: #fff; background: var(--accent); border-radius: 6px; padding: 8px 12px; cursor: pointer; }
.td-btn.ghost { background: transparent; color: var(--accent); }
.td-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.td-btn.pulse { animation: td-pulse 0.9s ease; }

.td-modal { position: absolute; inset: 0; z-index: 5; display: flex; align-items: center; justify-content: center; padding: 12px; background: color-mix(in srgb, var(--ink) 34%, transparent); }
.td-dialog { width: min(330px, 94%); background: var(--panel); border: 1px solid var(--line-bright); border-radius: 10px; padding: 16px; box-shadow: 0 14px 34px rgba(0, 0, 0, 0.28); }
.td-dialog-h { font: 600 14px var(--sans); color: var(--ink); }
.td-dialog-p { font-size: 12.5px; line-height: 1.55; color: var(--muted); margin: 8px 0 0; }
.td-dialog-row { display: flex; justify-content: flex-end; gap: 8px; margin-top: 14px; }
.td-picklist { margin-top: 12px; border: 1px solid var(--line); border-radius: 7px; overflow: hidden; }
.td-pick { padding: 9px 11px; font: 500 12px var(--mono); color: var(--muted); border-bottom: 1px solid var(--line); }
.td-pick:last-child { border-bottom: 0; }
.td-pick.is-trex { color: var(--ink); cursor: pointer; }
.td-pick.is-trex:hover { background: var(--accent-dim); }
.td-pick.sel { background: var(--accent); color: #fff; }
.td-pick:not(.is-trex) { opacity: 0.5; }

/* step 3: the style preference picker (accent swatches + light/dark) */
.td-style { border-top: 1px solid var(--line); padding: 15px; }
.td-style-h { font-size: 13.5px; line-height: 1.5; color: var(--ink); }
.td-style-row { display: flex; gap: 26px; margin-top: 13px; flex-wrap: wrap; }
.td-style-grp { display: flex; flex-direction: column; gap: 8px; }
.td-style-lab { font: 600 10px var(--mono); letter-spacing: 0.1em; text-transform: uppercase; color: var(--faint); }
.td-swatches { display: flex; gap: 8px; }
.td-sw { width: 26px; height: 26px; padding: 0; border-radius: 50%; border: 2px solid transparent; background: var(--sw);
  cursor: pointer; box-shadow: inset 0 0 0 2px var(--panel); transition: transform 0.1s; }
.td-sw:hover { transform: scale(1.09); }
.td-sw.is-on { border-color: var(--ink); }
.td-seg { display: inline-flex; border: 1px solid var(--line); border-radius: 7px; overflow: hidden; }
.td-segbtn { font: 600 11.5px var(--mono); padding: 6px 14px; border: 0; background: var(--panel); color: var(--muted); cursor: pointer; }
.td-segbtn + .td-segbtn { border-left: 1px solid var(--line); }
.td-segbtn.is-on { background: var(--accent); color: #fff; }

/* the payoff: hosted URL, the .trex, and the create-an-account CTA */
.td-payoff { margin: 0 15px 15px; padding: 15px 16px; border-radius: 10px;
  border: 1px solid color-mix(in srgb, var(--accent) 45%, var(--line)); background: var(--accent-dim); }
.td-pay-h { font: 600 14px var(--sans); color: var(--ink); }
.td-pay-rows { margin-top: 12px; display: flex; flex-direction: column; gap: 8px; }
.td-pay-row { display: flex; align-items: center; gap: 9px; flex-wrap: wrap; }
.td-pay-k { flex: 0 0 auto; min-width: 64px; font: 600 10px var(--mono); letter-spacing: 0.1em; text-transform: uppercase; color: var(--faint); }
/* scoped past `.sheet-card code` so these stay panel chips, not accent-dim pills */
.td-payoff .td-pay-v { font: 600 12px var(--mono); color: var(--ink); background: var(--panel); border: 1px solid var(--line); border-radius: 5px; padding: 5px 9px; word-break: break-all; }
/* the Hosted-at value is a real link to the live demo, so it reads as clickable */
.td-payoff .td-pay-link { text-decoration: none; cursor: pointer; }
.td-payoff .td-pay-link:hover { border-color: var(--accent); color: var(--accent); }
.td-pay-dot { width: 7px; height: 7px; border-radius: 50%; background: #0F9D6B; }
.td-pay-live { font: 600 10.5px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; color: #0F9D6B; }
.td-pay-copy { font: 600 10px var(--mono); letter-spacing: 0.06em; text-transform: uppercase; border: 1px solid var(--accent);
  color: var(--accent); background: transparent; border-radius: 4px; padding: 5px 10px; cursor: pointer; }
.td-pay-copy:hover { background: var(--accent); color: #fff; }
.td-pay-note { font-size: 13px; line-height: 1.58; color: var(--muted); margin-top: 12px; }
.td-pay-note b { color: var(--ink); font-weight: 600; }
.td-pay-cta { display: inline-block; margin-top: 13px; text-decoration: none; }

.td-intro { padding: 26px 22px 30px; text-align: center; }
.td-intro-t { font: 600 clamp(18px, 3vw, 22px) var(--sans); letter-spacing: -0.01em; color: var(--ink); }
.td-intro-p { max-width: 54ch; margin: 9px auto 17px; font-size: 13.5px; line-height: 1.6; color: var(--muted); }

.td-right { min-width: 0; }
.td-hold { height: 100%; min-height: 178px; display: flex; align-items: center; justify-content: center; text-align: center; padding: 16px; border: 2px dashed color-mix(in srgb, var(--accent) 26%, var(--line)); border-radius: 9px; }
.td-hold div { font: 500 12.5px/1.65 var(--mono); color: var(--faint); }
.td-hold b { color: var(--muted); }

.td-num { display: inline-flex; align-items: center; justify-content: center; width: 18px; height: 18px; margin-right: 5px; border-radius: 50%; background: var(--accent); color: #fff; font: 700 11px var(--mono); vertical-align: 1px; }
.td-btn.nudge { animation: td-pulse 1.2s ease infinite; }

@keyframes td-pulse { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.05); } }
@media (prefers-reduced-motion: reduce) { .td-btn.pulse, .td-btn.nudge, .td-sw { animation: none; transition: none; } }
@media (prefers-color-scheme: dark) { .td-canvas { background: #0b1220; } }

/* ---- park-it shelf: the learner saves an artifact (URL, prompt, …) ---- */
.park { margin-top: 18px; border: 1px solid var(--line); border-radius: 8px; padding: 14px 16px; background: var(--panel); }
.park .plabel { font: 600 10.5px var(--mono); letter-spacing: 0.12em; text-transform: uppercase; color: var(--faint); }
.park .prow { display: flex; gap: 8px; margin-top: 8px; flex-wrap: wrap; }
.park input { flex: 1; min-width: 200px; font: 500 13px var(--mono); color: var(--ink); background: var(--bg); border: 1px solid var(--line); border-radius: 5px; padding: 8px 11px; }
.park input:focus { outline: none; border-color: var(--accent); }
.park .psave { font: 600 11px var(--mono); letter-spacing: 0.06em; border: 1px solid var(--accent); color: var(--accent); background: transparent; border-radius: 5px; padding: 0 14px; cursor: pointer; }
.park .psave:hover { background: var(--accent); color: #fff; }
.park .pnote { margin-top: 7px; font-size: 12.5px; color: var(--faint); }
.park.saved { border-color: color-mix(in srgb, var(--accent) 45%, var(--line)); }

/* ---- controls: prev / next + the sheet tab strip (the "workbook" gag) ---- */
.lnav { display: flex; align-items: center; gap: 12px; margin-top: 18px; }
.lnav .sp { flex: 1; }
.lbtn {
  font: 600 13px var(--mono); letter-spacing: 0.04em; padding: 10px 18px; border-radius: 6px;
  border: 1px solid var(--line); background: var(--panel); color: var(--ink); cursor: pointer; text-decoration: none;
}
.lbtn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
.lbtn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.lbtn.primary:hover { filter: brightness(1.08); color: #fff; }
.lbtn:disabled { opacity: 0.4; cursor: not-allowed; }

.tabstrip { display: flex; gap: 2px; margin-top: 16px; overflow-x: auto; padding-bottom: 4px; border-top: 1px solid var(--line); padding-top: 10px; }
.tab {
  flex: none; font: 500 11px var(--mono); color: var(--faint); background: var(--panel);
  border: 1px solid var(--line); border-bottom: 2px solid transparent; border-radius: 4px 4px 0 0;
  padding: 6px 11px; cursor: pointer; white-space: nowrap; transition: color 0.1s, border-color 0.1s;
}
.tab:hover { color: var(--ink); }
.tab.on { color: var(--accent); border-bottom-color: var(--accent); background: var(--accent-dim); }
.tab.done::before { content: '✓ '; color: var(--accent); }
.tab.locked { opacity: 0.6; }
.tab.locked::before { content: '🔒 '; font-size: 9px; }
.tab.locked:hover { color: var(--faint); }

/* ---- the paywall sheet (freemium variant; markup from lesson-render.ts) ---- */
.locked-sheet .lock-perks { list-style: none; margin: 14px 0 0; padding: 0; }
.locked-sheet .lock-perks li { position: relative; padding: 0 0 0 18px; margin: 7px 0; font-size: 14.5px; line-height: 1.55; color: var(--muted); }
.locked-sheet .lock-perks li::before { content: '›'; position: absolute; left: 0; color: var(--accent); font-weight: 700; }
.locked-sheet .cta-row { margin-top: 20px; display: flex; gap: 12px; flex-wrap: wrap; }
.locked-sheet .lock-guar { margin-top: 14px; font-size: 13px; color: var(--faint); line-height: 1.6; }
.locked-sheet .lock-divider {
  display: flex; align-items: center; gap: 12px; margin: 30px 0 0;
  font: 600 11px var(--mono); letter-spacing: 0.14em; text-transform: uppercase; color: var(--faint);
}
.locked-sheet .lock-divider::before, .locked-sheet .lock-divider::after { content: ''; flex: 1; height: 1px; background: var(--line); }
.locked-sheet .lock-form { display: flex; gap: 8px; margin: 16px 0 0; flex-wrap: wrap; }
.locked-sheet .lock-form input { flex: 1; min-width: 220px; font: 500 13px var(--mono); color: var(--ink); background: var(--panel); border: 1px solid var(--line); border-radius: 6px; padding: 11px 13px; }
.locked-sheet .lock-form input:focus { outline: none; border-color: var(--accent); }
.locked-sheet .lock-form button { font: 600 13px var(--mono); border: 1px solid var(--accent); background: var(--accent); color: #fff; border-radius: 6px; padding: 0 20px; cursor: pointer; }
.locked-sheet .lock-form button:hover:not(:disabled) { filter: brightness(1.08); }
.locked-sheet .lock-form button:disabled { opacity: 0.55; cursor: default; }
.locked-sheet .lock-msg { min-height: 1.2em; font-size: 14px; }
.locked-sheet .lock-msg.err { color: #8b3a3a; }
.locked-sheet .lock-msg.ok { color: var(--accent); }
.locked-sheet .lock-alt { margin-top: 18px; font-size: 13.5px; color: var(--faint); }
.locked-sheet .lock-alt a { color: var(--accent); }

/* ---- the finish state ---- */
.finish { text-align: center; padding: 20px 0 6px; }
.finish h2 { justify-content: center; }
.finish .big { font: 600 clamp(26px, 5vw, 40px)/1.1 var(--sans); color: var(--ink); letter-spacing: -0.02em; }
.finish .big .em { color: var(--accent); }
.finish .cta-row { margin-top: 22px; display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.lfoot { margin-top: 30px; padding: 22px 0 48px; border-top: 1px solid var(--line); text-align: center; font: 500 11.5px var(--mono); color: var(--faint); letter-spacing: 0.05em; }
.lfoot a { color: var(--muted); }